U.S. patent application number 14/569919 was filed with the patent office on 2016-06-16 for cooling fan vane assembly for a resistor grid.
This patent application is currently assigned to Dayton-Phoenix Group, Inc.. The applicant listed for this patent is Gabriel E. Widmer, Justin P. Widmer. Invention is credited to Gabriel E. Widmer, Justin P. Widmer.
Application Number | 20160167525 14/569919 |
Document ID | / |
Family ID | 56110362 |
Filed Date | 2016-06-16 |
United States Patent
Application |
20160167525 |
Kind Code |
A1 |
Widmer; Justin P. ; et
al. |
June 16, 2016 |
Cooling Fan Vane Assembly for a Resistor Grid
Abstract
A cooling fan vane assembly for a resistor grid may include a
duct having a substantially round inlet opening, a substantially
rectangular outlet opening, and a side wall extending between the
inlet opening and the outlet opening shaped to transition from a
substantially round shape to a substantially rectangular shape; the
inlet opening including a plurality of radially extending turning
vanes; and a frustoconical vane positioned in the duct adjacent a
downstream side of the plurality of radially extending vanes.
Inventors: |
Widmer; Justin P.; (Battle
Ground, IN) ; Widmer; Gabriel E.; (West Lafayette,
IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Widmer; Justin P.
Widmer; Gabriel E. |
Battle Ground
West Lafayette |
IN
IN |
US
US |
|
|
Assignee: |
Dayton-Phoenix Group, Inc.
Dayton
OH
|
Family ID: |
56110362 |
Appl. No.: |
14/569919 |
Filed: |
December 15, 2014 |
Current U.S.
Class: |
415/1 ;
415/211.2 |
Current CPC
Class: |
F04D 29/547 20130101;
B60L 1/02 20130101; B60L 7/02 20130101; F04D 29/542 20130101; F04D
29/545 20130101 |
International
Class: |
B60L 7/02 20060101
B60L007/02; F04D 29/54 20060101 F04D029/54; F04D 29/32 20060101
F04D029/32; F04D 19/00 20060101 F04D019/00; F04D 25/08 20060101
F04D025/08 |
Claims
1. A cooling fan vane assembly for a resistor grid, the vane
assembly comprising: a duct having a substantially round inlet
opening, a substantially rectangular outlet opening, and a side
wall extending between the inlet opening and the outlet opening
shaped to transition from a substantially round shape to a
substantially rectangular shape; the inlet opening including a
plurality of radially extending turning vanes; and a frustoconical
vane positioned in the duct adjacent a downstream side of the
plurality of radially extending vanes.
2. The vane assembly of claim 1, wherein the frustoconical vane
includes a substantially annular side wall that tapers in diameter
from an upstream end of the frustoconical vane to a downstream end
of the frustoconical vane.
3. The vane assembly of claim 2, wherein the frustoconical vane is
shaped to extend into a transition region between the substantially
round inlet opening and the substantially rectangular outlet
opening.
4. The vane assembly of claim 3, wherein the frustoconical vane has
a taper angle of approximately 20.degree. relative to a centerline
of the duct.
5. The vane assembly of claim 4, wherein the frustoconical vane has
a length-to-diameter ratio at the upstream end of approximately
2:7.
6. The vane assembly of claim 1, wherein the inlet opening includes
a substantially cylindrical wall segment; and radially outer ends
of the plurality of radially extending vanes are attached to the
cylindrical wall segment.
7. The vane assembly of claim 6, wherein the inlet opening includes
an inner stiffening ring attached to the radially inner ends of the
plurality of radially extending vanes.
8. The vane assembly of claim 7, wherein the inner stiffening ring
corresponds in diameter to an outer diameter of a hub of an
associated cooling fan.
9. The vane assembly of claim 8, wherein the radially extending
vanes have a length that is approximately equal to the length of
blades of the associated cooling fan.
10. The vane assembly of claim 9, wherein the radially extending
vanes are plate shaped.
11. The vane assembly of claim 10, wherein the radially extending
vanes are angled relative to a plane containing a centerline of the
duct.
12. The vane assembly of claim 11, wherein the frustoconical vane
is mounted on one or more of the plurality of radially extending
vanes.
13. The vane assembly of claim 12, wherein the frustoconical vane
is attached at the upstream end thereof to downstream edges of one
or more of the plurality of radially extending vanes.
14. The vane assembly of claim 13, wherein the upstream end of the
frustoconical vane is positioned at approximately midpoints of the
plurality of radially extending vanes, measured in a radial
direction.
15. A vehicle comprising: a duct having a substantially round inlet
opening, a substantially rectangular outlet opening, and a side
wall extending between the inlet opening to the outlet opening
shaped to transition from a substantially round shape to a
substantially rectangular shape; the inlet opening including a
plurality of radially extending vanes; and a frustoconical vane
positioned in the duct adjacent a downstream side of the plurality
of radially extending vanes.
16. The vehicle of claim 15, wherein the vehicle is selected from a
diesel-electric locomotive traction engine, and a diesel-electric
truck.
17. The vehicle of claim 15, further comprising a cooling fan
having a hub and radially extending blades, the cooling fan
positioned adjacent the duct such that rotation of the hub and
blades directs cooling air into the inlet opening of the duct.
18. The vehicle of claim 17, further comprising a braking grid
having a resistor element, the braking grid positioned adjacent the
outlet opening of the duct.
19. The vehicle of claim 18, wherein the radially extending vanes
and the frustoconical vane are shaped to direct cooling air from
the cooling fan uniformly across the resistor element.
20. The vehicle of claim 19, wherein the frustoconical vane is
shaped to extend into a transition region between the substantially
round inlet opening and the substantially rectangular outlet
opening.
21. The vehicle of claim 20, wherein the frustoconical vane has a
taper angle of approximately 20.degree. relative to a centerline of
the duct.
22. A method of cooling a dynamic braking grid, the method
comprising: providing a fan having a hub supporting a plurality of
fan blades; positioning a duct adjacent the fan, the duct having a
substantially round inlet opening corresponding in diameter to an
outer diameter of the plurality of fan blades, a substantially
rectangular outlet opening adjacent the dynamic braking grid, and a
side wall extending between the inlet opening and the outlet
opening shaped to transition from a substantially round shape to a
substantially rectangular shape corresponding to a shape of the
dynamic braking grid to guide cooling air blown by the fan to the
dynamic braking grid; providing the inlet opening including a
plurality of radially extending vanes shaped and angled to direct
the cooling air in a substantially axial direction relative to the
fan hub; and providing a frustoconical vane positioned in the duct
adjacent a downstream side of the plurality of radially extending
vanes, and shaped to distribute cooling air evenly across the
dynamic braking grid.
Description
TECHNICAL FIELD
[0001] This disclosure relates to devices and methods for cooling
resistive elements that dissipate heat energy and, more
particularly, to systems and methods for cooling dynamic braking
grids of a type used with electric fraction motors.
BACKGROUND
[0002] Large vehicles, such as diesel-electric locomotives and
diesel-electric off-highway trucks, such as mining trucks, may be
powered by electric traction motors. Electric traction motors for
such vehicles may use an alternating current (AC) electric motor
powered by either an alternating current alternator-rectifier or a
direct current (DC) generator that in turn is powered by a diesel
engine. Vehicles powered by such diesel-electric traction motors
commonly use dynamic or rheostatic braking systems. In a dynamic
braking system, the armature of each traction motor is connected
across a forced-air-cooled resistance grid, known as a dynamic
braking grid. In a diesel-electric locomotive, the dynamic braking
grid typically is located behind the cab.
[0003] To brake a diesel-electric engine with a dynamic braking
system, the electric traction motor is connected to function as an
electric power generator that is driven by the rotating wheels of
the moving vehicle. The electricity generated by the traction motor
is conducted to the braking grid, which is a frame containing a
resistance element in the form of thin metal plates connected in
series. The metal plates are made of a material that is
electrically conductive, but provides resistance to the current
received from the traction motor so that the current is converted
to heat that is radiated from the resistor elements.
Diesel-electric engines usually employ multiple braking grids.
Thus, the energy of motion of the locomotive engine, or other
vehicle in which this configuration is installed, is converted to
heat in the dynamic braking operation mode that is dissipated from
the resistance element plates.
[0004] An issue that arises when dynamic braking systems are
employed to brake a vehicle, such as a locomotive, traveling at
high speed, or when the dynamic braking system is applied to a
vehicle traveling downwardly on a relatively steep grade, is that
the dynamic braking grid may overheat. Cooling fans typically are
employed to direct ambient cooling air across the resistance
elements of a dynamic braking grid to maintain the temperature of
the resistance elements below a temperature at which damage to the
resistance elements or other components of the braking system might
occur.
[0005] The frame containing the plate-shaped resistance elements of
dynamic braking grids typically is rectangular in shape, whereas
the cooling fan utilizes a circular turbine to move air over the
resistance elements. The circular turbine typically has a central
circular hub and a plurality of radially extending fan blades. It
is necessary to direct the air flow from the circular cooling fan
evenly across the rectangular braking grid. If the air flow from
the cooling fan flows unevenly over the resistance elements, hot
spots that might occur on the resistor elements in areas with
relatively low air flow. Cooling fans typically utilize a duct that
encloses stationary vanes to direct air from the turbine of the
cooling fan across the rectangular braking grid. Accordingly, there
is a need for a cooling fan vane assembly for a resistor grid that
effectively and efficiently distributes cooling air evenly across a
resistor grid to dissipate heat generated by rheostatic
braking.
SUMMARY
[0006] In one embodiment, the disclosed cooling fan vane assembly
for a resistor grid may include a duct having a substantially round
inlet opening, a substantially rectangular outlet opening, and a
side wall extending between the inlet opening and the outlet
opening shaped to transition from a substantially round shape to a
substantially rectangular shape; the inlet opening including a
plurality of radially extending vanes; and a frustoconical vane
positioned in the duct adjacent a downstream side of the plurality
of radially extending vanes.
[0007] In another embodiment, a vehicle may include a duct having a
substantially round inlet opening, a substantially rectangular
outlet opening, and a side wall extending between the inlet opening
and the outlet opening shaped to transition from a substantially
round shape to a substantially rectangular shape; the inlet opening
includes a plurality of radially extending vanes; and a
frustoconical vane positioned in the duct adjacent a downstream
side of the plurality of radially extending vanes.
[0008] In yet another embodiment, a method of cooling a dynamic
braking grid may include providing a fan having a hub supporting a
plurality of fan blades; positioning a duct adjacent the fan, the
duct having a substantially round inlet opening corresponding in
diameter to an outer diameter of the plurality of fan blades, a
substantially rectangular outlet opening adjacent the dynamic
braking grid, and a side wall extending between the inlet opening
and the outlet opening shaped to transition from a substantially
round shape to a substantially rectangular shape corresponding to a
shape of a dynamic braking grid to guide cooling air blown by the
fan to the dynamic braking grid; providing an inlet opening
including a plurality of radially extending vanes shaped and angled
to direct the cooling air in a substantially axial direction
relative to the fan hub; and providing a frustoconical vane
positioned in the duct adjacent a downstream side of the plurality
of radially extending vanes and shaped to distribute cooling air
evenly across the dynamic braking grid.
[0009] Other objects and advantages of the disclosed cooling fan
vane assembly for a resistor grid will be apparent from the
following description, the accompanying drawings, and the appended
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is an exploded, perspective view of the disclosed
cooling fan vane assembly for a resistor grid;
[0011] FIG. 2 is a side elevation in section of the cooling fan
vane assembly for a resistor grid disclosed in FIG. 1;
[0012] FIG. 3 is a side elevation of the frustoconical vane of the
cooling fan vane assembly for a resistor grid of FIG. 1; and
[0013] FIG. 4 is a plan view of the frustoconical vane shown in
FIG. 3.
DETAILED DESCRIPTION
[0014] As shown in FIGS. 1 and 2, the disclosed cooling fan vane
assembly for a resistor grid, generally designated 10, may be
configured to be mounted in a vehicle 12, such as a diesel-electric
vehicle. Diesel-electric vehicles may include a diesel-electric
locomotive traction engine and a diesel-electric truck, such as an
off-highway truck, and more particularly a diesel-electric
off-highway mining truck. The cooling fan vane assembly 10 may
include a duct 14 having a round or substantially round inlet
opening 16, a rectangular or substantially rectangular outlet
opening 18, and a side wall 20. The side wall 20 may be continuous
and imperforate, may extend between the inlet opening 16 and the
outlet opening 18, and in embodiments may be shaped to transition
from a round or substantially round shape adjacent the inlet
opening to a rectangular or substantially rectangular shape
adjacent the outlet opening. The rectangular or substantially
rectangular shape may take the form of a square or substantially
square shape.
[0015] The inlet opening 16 may include a plurality of radially
extending, or substantially radially extending, vanes 22. The vanes
22 may be spaced about the inner periphery of the inlet opening 16,
and in embodiments may be spaced evenly about the inner periphery
of the inlet opening. The vanes 22 in embodiments may be plate
shaped, and may be angled relative to a centerline A of the vane
assembly 10, which coincides with the direction of air flow through
the vane assembly.
[0016] In an embodiment, the inlet opening 16 may include a
substantially cylindrical wall segment 24 that may be attached to a
substantially flat mounting plate 25. The mounting plate may be
used to attach the vane assembly 10 to a bulkhead (not shown) of
the vehicle 12. The radially outer ends 26 of each of the plurality
of radially extending vanes 22 may be attached to the radially
inner surface of the cylindrical wall segment 24 by one or more of
welding, brazing, adhesives, mechanical fasteners such as rivets
and nut and bolt combinations, or other well-known means. The inlet
opening 16 also may include an inner stiffening ring 28 that may be
attached to one or more, and preferably all, of the radially inner
ends 30 of the radially extending vanes 22. The inner stiffening
ring 28 may be attached to the vanes 20 by one or more of welding,
brazing, adhesives, mechanical fasteners such as rivets and nut and
bolt combinations, or other well-known means.
[0017] The cooling fan vane assembly 10 also may include a
frustoconical vane 32. The frustoconical vane 32 may be positioned
in the duct 14 adjacent a downstream (i.e., in the direction of air
flow along centerline A) side of the plurality of radially
extending vanes 22. In an embodiment, the frustoconical vane 32 may
include a continuous, imperforate, substantially annular side wall
34 that tapers in diameter from an upstream end 36 to a downstream
end 38. In an embodiment, the side wall 34 may form an angle B (see
FIG. 3) of approximately 70.degree. with the upstream end 36 of the
frustoconical vane 32, so that the taper angle is approximately
20.degree. relative to the centerline A (see FIG. 2). The
frustoconical vane 32 may be shaped to extend into a transition
region 40 between the substantially round inlet opening 16 and
cylindrical wall segment 24 and the substantially rectangular
outlet opening 18 of the duct 14. In one particular embodiment, the
ratio of the length or height of the frustoconical vane 32
(measured in the direction of arrow A) to the diameter of the
frustoconical vane at the upstream end 36 is approximately 2:7. The
frustoconical vane 32, as well as the entire cooling fan vane
assembly 10, may be made of a mild steel, such as a 12 gauge mild
steel.
[0018] The vane assembly 10 may be positioned adjacent and
downstream of a cooling fan 42 having an electric motor 44 that
drives a turbine 46 mounted on an output shaft 48 of the motor. In
an embodiment, the inlet opening 16 of the duct 14 is immediately
adjacent the turbine 46 of the cooling fan 42; that is, there is no
intervening structure. The turbine 46 may include an annular hub 50
to which a plurality of radially extending turbine blades 52 is
attached to its radially outer surface. The turbine blades 52 may
be connected at their roots to, and positioned about, the radially
outer surface of the hub 50, and in an embodiment may be spaced
evenly about the outer surface.
[0019] In an embodiment, the inner stiffening ring 28 of the vane
assembly 10 corresponds in diameter to an outer diameter of the hub
50, as best shown in FIG. 2. That is, the diameter of the inner
stiffening ring 28 may be approximately the same as the outer
diameter of the hub 50 of the cooling fan 42. Also in an
embodiment, the radially extending vanes 22 of the vane assembly 10
each have a length, measured in a radial direction from the
centerline A of the vane assembly, that is approximately equal to
the lengths of the blades 52 of the turbine 46 of the cooling fan
42. In an embodiment, the centerline A of the vane assembly 10 is
the same as (i.e., coincides with) a centerline of the turbine 46
of the cooling fan 42, and in still other embodiments may be the
same as the centerlines of the output shaft 48 and motor 44.
Consequently, the vanes 22 are aligned with the blades 52 of the
cooling fan in a longitudinal or airflow direction, so that the
radially inner ends 28 of the vanes 22 are aligned with the
radially inner ends, or roots, of the blades 52, and the radially
outer ends 26 of the vanes are aligned with the radially outer
ends, or tips, of the blades.
[0020] In an embodiment, the frustoconical vane 32 may be mounted
on one or more--and in a particular embodiment, all--of the
plurality of radially extending vanes 22 (see FIG. 2). In a
particular embodiment, the frustoconical vane 32 may be attached at
its upstream end 36 to one or more, and in one embodiment all, of
the downstream edges 54 of the plurality of radially extending
vanes 22. The frustoconical vane 32 may be attached to the one or
more downstream edges 54 of the radially extending vanes 22 by one
or more of welding, brazing, adhesives, mechanical fasteners such
as rivets or nut and bolt combinations, or other well-known means.
In one particular embodiment, the frustoconical vane 32 may be
concentric relative to the centerline A and thus the vane assembly
10; the upstream end 36 of the frustoconical vane contacts, and may
be attached to, the radially extending vanes 22 at approximately
the radial midpoints of the downstream edges 54.
[0021] As shown in FIGS. 1 and 2, the duct 14 may be positioned
within the vehicle 12 adjacent a dynamic braking grid 56 having a
plurality of resistor elements 58 connected in series and supported
within a frame 60. In an embodiment, the braking grid 56 may have
two rows of resistor elements separated by an insulating bar 61. In
an embodiment, the outlet opening 18 of the duct 14 may be
immediately adjacent the dynamic braking grid 56; that is, there is
no intervening structure between the outlet opening and the dynamic
braking grid. Also in an embodiment, the rectangular shape of the
outlet opening 28 corresponds, or approximately corresponds, to the
shape and size of the upstream end 62 of the dynamic braking grid
56. In an embodiment, the outlet opening 18 of the duct 14 may
include a transverse stiffening strut 63 that spans the outlet
opening and is aligned with the insulating bar 61. The stiffening
strut 63 may taper in thickness in an upstream direction to divide
airflow through the duct 14 and direct it upwardly or downwardly
(FIG. 2) away from the insulating bar 61.
[0022] The dynamic braking grid 56 may in embodiments take the form
of multiple discrete braking grids, each having a frame 60
supporting a plurality of resistor elements 58 connected in series
along centerline A. The multiple frames 60 may be stacked spaced
from each other (in one embodiment about 6 inches) and in parallel
along centerline A so that their respective resistor elements,
which may be plate shaped, may be substantially parallel to each
other. The multiple frames 60 may be electrically connected to each
other in series, in parallel, or different circuitry, and in some
embodiments electrically connected to power the fan motor 44. In
such a multiple-grid embodiment, the outlet opening 18 of the duct
14 may be adjacent the upstream end 62 of the closest one of the
braking grids 56.
[0023] The cooling fan vane assembly 10 may be positioned within a
vehicle 12 such that the cooling fan 42 is adjacent the inlet
opening 16 of the duct 14 so that the rotation of the hub 50 and
blades 52 of the turbine 46 direct cooling air downstream from the
cooling fan along centerline A into the inlet opening of the duct.
In an embodiment, the radially extending vanes 22 and the
frustoconical vane 32 may be shaped to direct ambient air from the
cooling fan 42 uniformly across the resistor element of the braking
grid 56.
[0024] The foregoing cooling fan vane assembly 10 may be used to
cool the dynamic braking grid 56. The method may include providing
a cooling fan 42 having a hub 50 supporting a plurality of fan
blades 52. The duct 14 may be positioned adjacent the cooling fan
42. The duct 14 may have a substantially round inlet opening 16
corresponding in diameter to an outer diameter of the plurality of
fan blades 52, a substantially rectangular outer opening 18
adjacent the dynamic braking grid 56, and a side wall 20 extending
between the inlet opening 16 and the outlet opening 18, and shaped
to transition from a substantially round shape to a substantially
rectangular shape corresponding in dimension (i.e., length, width,
and geometric shape) to a shape of the dynamic braking grid to
guide cooling air blown by the fan 42 to the dynamic braking
grid.
[0025] The inlet opening 16 may be provided with a plurality of
radially extending vanes 22 shaped and angled to direct cooling air
from the fan 42 in a substantially axial direction (that is, in a
direction parallel to and along the centerline A) relative to the
fan hub 50. A frustoconical vane 32 may be positioned in the
transition region 40 of the duct 14 adjacent the downstream side of
the radially extending vanes 22. The frustoconical vane 32 may be
shaped to distribute cooling air evenly across the dynamic braking
grid 56.
[0026] Without being limited to any specific theory of operation,
from an inspection of FIG. 2 the frustoconical vane 32 is shaped
and positioned to direct cooling air from the fan 42 toward the
center of the dynamic braking grid 56. The blades 52 of the turbine
46 push cooling air across fixed vanes 22, but not across the
center portion of the opening 16 radially inward of the stiffening
ring 28, so the turbine does not blow cooling air directly toward
the center of the braking grid 56. The tapered wall 34 (FIGS. 3 and
4) of the frustoconical vane 32 diverts a portion of the cooling
air from the outer periphery of the inlet opening 16 flowing
through the vanes 22 toward the center of the duct 14 and across
the center of the dynamic braking grid 56, where the diverted
portion of the cooling air flows across the portion of the resistor
elements 58 located at the center of the dynamic braking grid.
[0027] The combination of the frustoconical vane 32 and the angled,
radially extending vanes 22 distributes the cooling air from the
fan 42 evenly across the face of the braking grid 56. The uniform
air movement minimizes or eliminates hot spots that might otherwise
occur on the resistor elements of the braking grid 56 during a
braking operation. By providing uniform airflow across the face of
the braking grid 56, the maximum temperature range, and hence the
maximum braking effect, of the braking grid 56 may be increased.
Further, by mounting the frustoconical vane 32 on the vanes 22,
there is no support structure extending directly from the
frustoconical vane to the wall 20 of the duct 14, and none is
required.
[0028] While the forms of apparatus and methods disclosed may
constitute preferred embodiments of the cooling fan vane assembly
for resistor grid, it is to be understood that the invention is not
limited to these precise forms of apparatus and methods, and that
changes may be made therein without departing from the scope of the
invention.
* * * * *